Internal-combustion engine



o STATES Patented JESSE G'. VINCENT, OF DETROIT, MICHIGAN, AISSIGNOR TO `PACKARD MOTOR CAB-COM- ?ANY, OF DETROIT, MICHIGAN, A. CORPORATION OF MICHIGAN..

INTERNAL-COMBUSTION ENGINE.

' Application l-ed October 8, 1924.'. Serial No. 742,372.

This invention relates to internal combustion engines and particularly to valve mechamsm.

The valve mechanism of an internal combustion engine usually comprises poppet valves'and a camshaft together with means such as tappet mechanism for operating the valve from the camshaft. The valve is usually closed by a spring and the cam operates to open it against the spring action. In this mechanism there must be a slight'clearance between the tappet mechanism and the valve or between the camshaft and the tappet mechanismsin order'that the valve may be certain to close on its seat. If thi'sclearance is not provided the valve will ride and consequently will not close tightlyfwith` the result that the port will leak and the valve be burned. The horsepower of the engine will also fall off dueto the fact' that full compression cannot obtained.

If the tappetniechanism is adjustedfor the proper clearance when the engine is cold, this clearance will sometimes beta-ken up 5 entirelyv by elongation of the valve :stem

when the engine gets hot. This necessitates a` greater amount of clearance being provided when the motor is cold with the result that this greater'clearance causes a clicking` ac- 3G tion' and thus makes the engine disagreeably noisy. Various means have been provided for automatically taking up this clearance or damping its action to mitigate the Anoise dificulty but none of these have proven entirely satisfactory due 4to the complication involved and the inoperativeness of some of them.

One of the objects of the present invention is to provide an automatic meansrfor taking operating mechanism while at thesame time providing for a firm closure or seating of the valve. Y

Another object of the invention is to pror vide a clearance take-up mechanism that is retracted during each opening and closing cycle of the valve, so that the valve may be insured of a firm seating.

Another object of the invention is to provide an automatic take-up for a valve mechanism together with .meansfor positively retracting the take-up means to thereby insure firm seating of the valve.

Another object of the invention is to pro- 5:? vide an automatic take-up means for a valve 11 and up the clearance between the valve and its mechanism, which .means is' arranged between the camshaft and the tappet mechamsm. v

Other objects of the invention will appear from' the following description-taken in connection with the drawings, which form a part of this specification, and in which:

AFig. 1 is a transverse section through an an engine cylinder mounte on a crankcase having a piston ..12 and a'connecting vrod 13. The cylinder is also provided with a cylinder port 14 which may be either an inlet or an exhaust port, and this port is closed by a popp'et valve 15 of7usua1 construction. The valve is guided in a guide 16 secured in .the cylinder casting and a spring-17 yield-v ingly retalns the valve in closed position as shown 1n the drawing.

The lower end of the valve stem is .indicated at 18 and this stem is operated upon to open the valve. by a tap et mechanism indicated generally at 19. T is mechanism comprises a guide 20 mounted in they crankcase 11, a sliding tappet 21 mounted in the guide, a tappet bolt 22 threaded into the tappet for longitudinal ad'ustment therein, anda nut 23 vfor locking t e bolt 22 in adjusted position. A cap 24 is also provided to prevent oil from.' working up around the tappet 21.

In the crankcase 11 is mounted a camshaft 25 which is operated in the usual way from the motor crankshaft, not shown in the v drawing. There is a cam 26 for-each of the valves of the engine, which cams are positioned to open and close the valves on the usual four-stroke cycle.

. Arranged between the camshaft 25 and the' tappet mechanism 19 is a rocker arm 27 which is pivoted :it-28 to a bearing member 29 of the crankcase.- This rocker arm bears lagainst the camshaft at the oint 30 and at its outer end it is bifurcate thus forming two separated arms 31. Between these arms 34. s shown in Fig. 2, the dog32 is'yieldingly pressed towards the right by a spring 35 arranged between a part of' the arm 2? and the dog. The upper end of the dog 32 is slightly beveled as at 36 and is arranged to bear against the lower end of the tappet 21. The bevel and the spring are so arranged that the dog is yieldingly pushed in between the pivot pin 33 and the valve tappet so that all clearance between these two parts is taken up and the valve tappet is lightly pressed upwardly against the lower end of the valve stem 18. f

Illhe dog 32 is also provided with a boss or projection 37 between the pin 33 and the camshaft 25, which projection is so arranged that the cam 26 will strike it just as the arm 27 is riding oil of thecam. 'Ihis position of the camshaft is shown in Fig. 2 where it will be seen that the cam has just left the contact part 30 ot the arm 27 and is now touching the projection 37 of the dog 32 so that the dog has been retracted tothe position shown in Fig. 2 andthe tappet mechanism 19 is dropped' down slightly to provide clearance between the tappet mechanism and the valve stem 18. This insures the firm closing of the poppet valve 18 by its spring 17. J ust as soon as the cam 26 passes the projection 37 the spring 35 will act to push the dog 3,6 towards the right in Fig. 2 and thus wedge the tappet mechanism 19 upwardly to again take up the clearance between the tappet mechanism and the valve stem. j

llhus it will be seen that the mechanism operates during the opening and closing cycle of the valve, to iirst take up the clearance between the camshaft and the valve stem and then tobe automatically retracted. In the form ot the invention shown this taking up of the clearance occurs immediately after the cam 26 passes the projection 37 and the retraction of the dog 32 occurs just as the valve is closing and this retraction of the dog is a-positive one just as the opening loli the valve itself is a positive action.

While I have herein described in some detail a specific embodiment of my invention, whichI deem to be new and advantageous and may specifically claim, I do not desire it to be .understood that my invention is limited to the exact details of the construction, as Qit will be apparent that changes may be made therein without departing from the spirit or scope ot my invention.

.Having thus described my invention, What I claim and desire 4to secure by Letters Pa-l tent is:

1. In an internal combustion engine, in combination, a valve adapted to `be opened and closed, a device for opening and closing the valve,and pivoted means between said device and the valve for taking up the clearance therebetween,v said means operating during the cyclel to automatically move out of engagement with the valve to insure firm seating of the valve. j

2. In an, internal combustion engine, m combination, a valve vadapted to be opened and closed, a device for opening and closing the valve, oscillatable means between said device and the valve for taking up the clearance therebetween, yand' means for positively freeing said take-up means from said valve during each opening and closing cycle of the valve.

3. In an engine, in combination, a valve device, means for operating the valve, and a rigid pivoted vtake-up means yieldingly pressed between said operating means and valve device.

4.-. In an engine, in combination, a valve device, a camshaft, and a rigid pivoted device adapted to engage the camshaft and said valve device for taking up the clearance therebetween.

5. In an engine, in combination, a valve device, a camshaft, a rocker arm between the camshaft and the valve device, and a pivoted device on the rocker arm normally yieldingly engaging said valve device for taking up the clearance.

' 6. In an engine, in combination, a valve device, means for operating the valve, and take-up means between said operating means and said valve device comprising a pivoted beveled dog.

7. In a valve operating mechanism, a pivoted arm, a dog pivoted to said arm. and a rotating cam adapted to successively engage said arm and said dog.

8. In combination, a reciprocating valve, and means adapted to actuate said valve, comprising an oscillatable dog adapted to engage said valve, and a member adapted to periodically move said dog into and out of engagement with said valve.

9. In an internal combustion engine, a valve device, a valve operating means, Yand take-up means between the valve device and the operating means comprising a pivoted member oscillatable in two directions.

10. In an internal combustion engine, a valve device, valve operating means, and take-up means between the valve device and the operating means comprising a pivoted member oscillatable in two directions in the same plane.

11. In an internal combustion engine, a valve device, a valve tappet, a. cam, a rocker arm intermediate the cam and valve tap et, and take-up means comprising a mem er pvoted upon the rocker arm and adapted for pivotal movement u on engagement ot the cam therewith. 7

12. In an internal combustion engine, inv

combination, a poppet valve, a valve tappet therefor, pivotedv means for operating the valve, and means associated with said op erating means and adapted to be moved into 1,osv,911

and out of engagement with the tappet for operating the tappet and valve and for taking up the clearance when the valve is seated.

13. In an internal combustion engine, in

'combinatiom a poppet valve, a valve tappet therefor, pivoted means for operating the valve and means carried by sald operating i operating the tappet and valve and for tak- 10 ing up the clearance when the valve is seated. In testimony whereof afl'x my signature.

vJESSE G. VINCENT. 

